The present inventive concept relates to a metal interconnection method of a semiconductor device, and more particularly, to a copper interconnection method of a semiconductor device.
With advances in integrated circuit semiconductor devices and fabrication processes, demand for higher device operation speed and higher device integration has increased. As one of various technologies for meeting the increasing demand for such faster operation speed and high integration, a semiconductor device with a dimension of several tens of nanometers has been commercialized. However, a decrease in the critical dimension (CD) results in an increase in the resistance of metal interconnections and an increase in the electrostatic capacitance between the metal interconnections. As a result, in such devices, it is difficult to realize the high-speed operation.
In order to solve this problem, copper (Cu) has been used in a metal interconnection process, instead of aluminum (Al), which was used as a metal interconnection material. The copper (Cu) has smaller resistivity and better electric conductivity than aluminum (Al). The currently used copper interconnection has not only an advantage of reducing RC (Resistance-Capacitance) time delay but has excellent EM (Electro-Migration) characteristics and an excellent high melting point characteristic, resulting in excellent reliability characteristics.
In the copper interconnection process, however, dry etching the copper in forming a metal pattern can be difficult. For this reason, the copper interconnection process forms patterns by forming trenches and via holes to bury the copper after forming an inter-metal dielectric.